I think it's of the utmost importance. The idea that this great teaching was passed down by a person who actually knew and saw the minds of man and the world for what it is, a person who understood the human condition and how to put an end to suffering. If some guys just got together and made the whole story up, then there's not much credibility to the practice, nor the idea of enlightenment.
I don't think Buddhism makes sense without the Buddha.
"As I reflected thus, my mind inclined to dwelling at ease, not to teaching the Dhamma.
"Then Brahma Sahampati, having known with his own awareness the line of thinking in my awareness, thought: 'The world is lost! The world is destroyed! The mind of the Tathagata, the Arahant, the Rightly Self-awakened One inclines to dwelling at ease, not to teaching the Dhamma!' Then, just as a strong man might extend his flexed arm or flex his extended arm, Brahma Sahampati disappeared from the Brahma-world and reappeared in front of me. Arranging his upper robe over one shoulder, he knelt down with his right knee on the ground, saluted me with his hands before his heart, and said to me: 'Lord, let the Blessed One teach the Dhamma! Let the One-Well-Gone teach the Dhamma! There are beings with little dust in their eyes who are falling away because they do not hear the Dhamma. There will be those who will understand the Dhamma.'
"That is what Brahma Sahampati said. Having said that, he further said this:
'In the past
there appeared among the Magadhans
an impure Dhamma
devised by the stained.
Throw open the door to the Deathless!
Let them hear the Dhamma
realized by the Stainless One!
Just as one standing on a rocky crag
might see people
all around below,
So, O wise
one, with all-around vision,
ascend the palace
fashioned of Dhamma.
Free from sorrow, behold the people
submerged in sorrow,
oppressed by birth & aging.
Rise up, hero, victor in battle!
O Teacher, wander without debt in the world.
Teach the Dhamma, O Blessed One:
There will be those who will understand.'
"Then, having understood Brahma's invitation, out of compassion for beings, I surveyed the world with the eye of an Awakened One. As I did so, I saw beings with little dust in their eyes and those with much, those with keen faculties and those with dull, those with good attributes and those with bad, those easy to teach and those hard, some of them seeing disgrace & danger in the other world. Just as in a pond of blue or red or white lotuses, some lotuses — born & growing in the water — might flourish while immersed in the water, without rising up from the water; some might stand at an even level with the water; while some might rise up from the water and stand without being smeared by the water — so too, surveying the world with the eye of an Awakened One, I saw beings with little dust in their eyes and those with much, those with keen faculties and those with dull, those with good attributes and those with bad, those easy to teach and those hard, some of them seeing disgrace & danger in the other world.
"Having seen this, I answered Brahma Sahampati in verse:
'Open are the doors to the Deathless
to those with ears.
Let them show their conviction...
- http://www.accesstoinsight.org/tipitaka ... .than.html
That verse always brings me to awe, it's inspiring.